1. Field of the Invention
The present invention relates to an apparatus and a method for providing a digital data stream associated with a video program, and in particular, an apparatus and a method for reading a digital data stream from a storage element having data stored according to a first standard, for example the DVD standard, and providing a digital data stream formatted in accordance with a digital television standard, for example the ATSC standard.
2. Related Art
Video signal processing systems that utilize storage media having digitally compressed video and audio information recorded thereon can give a user a vast number of options for controlling presentation of a program, or a video title, stored on such a media. One such system that is gaining rapid popularity comprises a video disc player adapted to process information stored in accordance with the digital video disc (DVD) specification. The information on a DVD formatted disc is recorded as discrete packets of data, in accordance with the DVD specification, wherein designated data packets carry information associated with various data streams, such as alternative video angles, audio tracks, sub-picture streams, etc. A video disc player reading a DVD formatted disc may be controlled to display or present certain packets of data and skip over others. Using digital processing techniques, the DVD system can use the digitally compressed data stored on the disc to seamlessly provide multiple variations of a program on a single disc to suit the preferences of the viewer.
FIG. 1 illustrates a conventional DVD player that provides an output signal to a television receiver adapted to process analog video signals. Generally, disc player 24 comprises motor and pickup assembly 26 which, under the control of servo processor 29, spins the disc and reads the information stored thereon. Preamp 27 and DVD data processing unit 28 translate the electrical pulses from motor and pickup assembly 26 into digital data that can be further processed by digital audio/video decoder unit 30. DVD data processing unit 28 typically performs functions such as demodulation, error correction and descrambling of the raw data read from the disc so that the data is in a suitable format for decoder unit 30.
Decoder unit 30 receives the demodulated, error corrected and descrambled data, processes the data, and provides the appropriate video and audio signals to a suitable display unit. Decoder unit 30 comprises data stream demultiplexer 32 which demultiplexes the data from data processing unit 28 into a plurality of separate data streams, including a video stream, an audio stream and a sub-picture stream, and provides the data streams to their respective data decoders. Video decoder 31 receives the video stream, decompresses the data, decodes the video data and provides a video signal to mixer 33. Sub-picture decoder 34 receives the sub-picture stream and provides data to on-screen display (OSD) control 35 which provides OSD video signals to mixer 33. The combined video signal from mixer 33 is provided to NTSC/PAL encoder 42 which generates a video signal that conforms to the appropriate analog video signal standard and provides the signal to a television receiver. Audio decoder 36 receives the audio streams from data stream demultiplexer 32 and provides the appropriate audio signals to an audio system. Microcontroller 40, which is coupled to system buffer 50, controls the operation of the various components of disc player 24. Typically, microcontroller 40 is also configured to control various access features of disc player 24. Microcontroller 40 may be embodied in an integrate circuit, including, but not limited to STI 5520, manufactured by SGS Thomson.
Also, digital television (DTV) standards have recently been developed to transmit and process high quality video, audio and ancillary data. Systems that utilize a digital television apparatus adapted to receive and process digital video signals offer a number of advantages over systems that utilize analog signals, including, improved picture resolution, ability to dynamically reallocate channel capacity among various data streams, and capability to add data streams to provide open ended extensibility of future services. One such DTV system is described by the ATSC standard A/53, 1995 (the “ATSC standard”), which specifies a system for transmitting data over a single 6 MHz channel. The ATSC standard utilizes a fixed length packet transport stream that is defined and optimized for DTV applications.
However, conventional DVD players are generally designed to operate with analog television systems and therefore may not be able to fully utilize the advantages associated with a DTV system. In particular, the resolution of a picture based on an analog signal may be significantly lower than the resolution of a picture based on a DTV compliant signal, for example an ATSC compliant signal. For example, an NTSC signal is formatted to display 525 interlaced lines at a rate of 30 frames per second. The ATSC standard allows for a number of higher resolution formats, including, 1080 lines at 1920 samples per line, 720 lines at 1280 samples per line and 483 lines at 720 samples per line. Although a DTV apparatus may also include components for processing and displaying analog signals, the resolution of the resulting picture will not match the picture resolution from a higher resolution digital format. As such, the NTSC or PAL compliant output signals of conventional DVD players can not fully realize the high definition (HD) display capabilities that may be possible in a DTV system. This represents a significant deficiency of conventional DVD players, especially in view of the growing trend toward digital television systems.
Therefore, what is needed is an apparatus and a method for storing data in a manner that allows the data to be easily read using conventional DVD player pick up components and may be easily modified for processing in a digital television apparatus.
In particular, what is needed is an apparatus and a method for storing data in a manner that includes features of the DVD standard which allows the data to be easily read using conventional DVD player pick up components and includes features of a digital television standard which allows the data to be easily modified for processing in a digital television receiver.
Also, what is needed is an apparatus for reading a digital data stream stored on a storage element, which includes features of the DVD standard and features of a digital television standard, and providing an output signal that conforms to the digital television standard.
EP 0600467A2 generally discloses a method for recording ATV signals onto the tracks of a video tape, wherein an application ID is recorded onto a timing sector of each track. The application ID stipulates a data structure for the data stored on the track. As such, different types of data can be recorded onto a particular video tape.
EP 0838926A2 discloses an apparatus and method for transmitting a pack of 2048 byte data pack using a digital interface according to the IEEE 1394 standard. In this connection, a 4 byte time stamp and 124 bytes of padding data are added to the 2048 byte pack, and then divided into a number of fractions that is a multiple of 2 thereby converting into a number of data blocks equal to the number of fractions. Each data block has a byte length of a multiple of 4. A CIP header and the like are added to a predetermined number of the data blocks to form a packet.